Grease composition and motion guiding device lubricated by grease composition

A grease composition for a clean environment, comprising a base oil, a thickener, and an extreme-pressure agent, wherein:

• the grease comprises:
• 1) a base oil in an amount of 40 to 95 mass % with respect to the total grease composition and the base oil has a kinematic viscosity at 40 degrees Celsius of 100 to 300 mm2/s;
• and the base oil comprises:
• a) at least 50 mass % of the base oil with respect to the total amount of the base oil is a hydrocarbon type synthetic oil;
• and
• b) the base oil is a mixture of a higher viscosity base oil having a kinematic viscosity at 40 degrees Celsius of 350 to 1600 mm2/s and a lower viscosity base oil of less than 350 mm2/s at 40 degrees Celsius, and at least 25 mass % of the base oil as a whole is the higher viscosity base oil;
• and
• 2) a lithium complex soap thickener in an amount of 20 to 40 mass % with respect to the total amount of the composition wherein the lithium complex soap thickener comprises at least 50 mass % of a fatty acid component of a hydroxy carboxylic acid;
• and
• 3) an extreme pressure agent which comprises at least one selected from the group consisting of molybdenum dithiocarbamates, molybdenum dithiophosphates, zinc dithiophosphates, and zinc dithiocarbamates, and the content of the extreme pressure agent is 0.1 to 10 mass % with respect to the total amount of the grease composition;
• and
• wherein the grease composition has a worked penetration of 200 to 400.